1. Field of the Invention
The present invention relates to an organic LED display panel production method, an organic LED display panel produced by the method, and a base film and a substrate for use in the method.
2. Description of the Related Art
In recent years, intensive research and development have been conducted on techniques for patterning an organic LED layer for production of a full-color organic LED display panel. Exemplary patterning techniques hitherto proposed are a masked evaporation method (e.g., Japanese Unexamined Patent Publication No. 8-227276 (1996)) and an ink jet method (e.g., Japanese Unexamined Patent Publication No. 10-12377 (1998)).
With the masked evaporation method, however, it is very difficulty to produce LED devices on a greater size substrate. Further, the ink jet method requires much time for producing LED devices on a greater size substrate.
To cope with these problems, there have been proposed transfer methods (e.g., Japanese Unexamined Patent Publications No. 10-208881 (1998), No. 11-237504 (1999) and No. 11-260549 (1999)) as patterning methods which can significantly reduce the time required for production of LED devices on a greater size substrate.
In organic LED display panel production methods employing the prior-art transfer methods, a donor film having a transfer film (e.g., an organic layer) is brought into intimate contact with a substrate, and then a laser beam or a heat radiation beam is applied to a desired portion of the transfer film of the donor film to pattern-transfer the transfer film onto the substrate. However, the prior-art methods encounter a problem such that a portion of the transfer film not irradiated with the laser beam or the heat radiation beam is undesirably transferred onto the substrate. That is, the transfer film is incorrectly pattern-transferred onto a portion of the substrate other than the irradiated portion, resulting in a patterning failure.
In view of the foregoing, it is an object of the present invention to provide an organic LED display panel production method which prevents the patterning failure in the transfer process and ensures that an organic LED layer is correctly patterned by the transfer method. It is another object of the invention to provide an organic LED display panel produced by the organic LED display panel production method, and a base film and a substrate for use in the method.
In accordance with the present invention to achieve the aforesaid objects, there is provided an organic LED display panel production method comprising the steps of: preparing a donor film by forming a transfer film on a base film comprising at least a foundation film and a light-to-heat conversion layer (light absorbing layer); and combining the donor film with a substrate and irradiating the donor film with one of a light beam and a heat radiation beam to pattern-transfer the transfer film from the donor film onto the substrate, wherein surfaces of the base film and the substrate which are to be brought into contact with the transfer film are hydrophilic or hydrophobic, and have water contact angles xcex81 and xcex82, respectively, which satisfy the following expression (I):
xcex81xe2x88x92xcex82 less than 50 degreesxe2x80x83xe2x80x83(I)
The organic LED display panel production method may further comprise the step of subjecting at least one of the surface of the base film and the surface of the substrate to one of a hydrophilation treatment and a hydrophobation treatment so that the expression (I) is satisfied.
The hydrophilation treatment or the hydrophobation treatment is selected from the group consisting of a UV treatment, a plasma treatment, a corona treatment, an F2 treatment and a chemical modification treatment.
Where the hydrophilation treatment or the hydrophobation treatment is the UV treatment, the UV treatment preferably employs a UV radiation having a wavelength of not greater than 310 nm.
Where the hydrophilation treatment or the hydrophobation treatment is the plasma treatment, the plasma treatment preferably employs argon or oxygen.
The present invention further provides an organic LED display panel produced by the organic LED display panel production method described above.
The present invention further provides a base film and a substrate for use in the organic LED display panel production method, the base film and the substrate being respectively composed of materials selected so that surfaces of the base film and the substrate to be brought into contact with the transfer film have water contact angles xcex81 and xcex82, respectively, which satisfy the expression (I) described above.
The present invention further provides a base film and a substrate for use in the organic LED display panel production method, the base film and the substrate having been subjected to one of a hydrophilation treatment and a hydrophobation treatment so that surfaces of the base film and the substrate to be brought into contact with the transfer film have water contact angles xcex81 and xcex82, respectively, which satisfy the expression (I) described above.